Iran's top negotiator said on Tuesday that a framework deal with world powers on its nuclear programme was "possible this week", although it would not be a disaster if there were a further delay.
Iran resumes negotiations in Geneva on Thursday with six world powers known as the "P5+1" - the United States, Russia, France, Britain, China and Germany. The talks are aimed at ending a standoff over the nuclear programme, which Western powers suspect may be aimed at developing nuclear weapons, despite Iran's denials.
"I believe there is a lot of work to be done. We have made some progress, but there is a great deal of mistrust in Iran concerning the attitude, behaviour and approach of some members of the P5+1," Foreign Minister Mohammad Javad Zarif told France 24 television during a visit to Paris.
"If we don't make a breakthrough at this round, it's not a disaster."
Since the relative moderate Hassan Rouhani was elected president in June, Iran has suggested greater willingness to negotiate a resolution to the standoff.
Zarif said all sides had boxed themselves into an unnecessary crisis over the last eight years, and reiterated that Tehran did not seek nuclear weapons.
"Even the perception that we are seeking nuclear weapons is detrimental to our security," he said.
Zarif, who met his French counterpart Laurent Fabius in Paris for the third time in as many months ahead of a speech at the UN cultural agency UNESCO on Wednesday, said a framework agreement could be achieved with political will on all sides.
"We need to see an end game that we can all agree on and take a first step on all sides," said Zarif, who is Iran's chief negotiator at the talks. "It's not that difficult to reach that agreement and it's even possible during this (Geneva) meeting."
He said recent talks with the UN nuclear watchdog, the IAEA, had been positive, as had a meeting between technical experts to prepare for Thursday's meeting in Geneva.
"I believe we have come very far, so we need to take a few more steps," he said. "We are prepared to take them in Geneva but, if we can't there, then in the next round."
French Foreign Ministry spokesman Romain Nadal said Fabius hoped the Geneva talks would lead to quick results.
"Iran must respond in a concrete and verifiable way to the concerns of the international community, because negotiations cannot be indefinite," Nadal said.
Paris has been one of the strongest advocates of sanctions to put pressure on Iran over its nuclear programme.
French President Francois Hollande was the first Western leader to meet President Rouhani during the annual meeting of the UN General Assembly in September.
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